Same deal - with "num_recv_frames=128,master_clock_rate=" +
str(samp_rate*4) I still get "ODD", just about every time.

On Thu, Nov 19, 2020 at 6:52 AM Ron Economos via USRP-users <
usrp-users@lists.ettus.com> wrote:

> The automatic setting of the master clock seems to be getting in the way
> after the PPS transition. Try explicitly setting the master clock.
>
> "num_recv_frames=128,master_clock_rate=" + str(samp_rate*4)
>
> Ron
> On 11/19/20 03:33, Josh via USRP-users wrote:
>
> Marcus,
>
> This is naked hardware - B210 usb into a pretty beefy laptop running
> Ubuntu 20.04, GNU Radio latest master (3.9)
> Even with num_recv_frames = 128, still getting "ODD" at startup of the
> flowgraph
>
> Any other optimizations I should be tuning?  Getting no overruns in the
> steady state, just at startup.
>
> Flowgraph is attached.
>
> Josh
>
> On Wed, Nov 18, 2020 at 4:46 PM Marcus D. Leech via USRP-users <
> usrp-users@lists.ettus.com> wrote:
>
>> On 11/18/2020 07:27 AM, Josh via USRP-users wrote:
>>
>> I'm seeing a difference in behavior between gr-uhd and plain uhd c++ api:
>>
>> Setup:
>> B210, 2 channels, 5MSPS, master_clock_rate 20MSPS, PPS sync
>> Receive only flowgraph
>>
>> With gr-uhd, there is always a "OOD" when the flowgraph first starts
>>
>> But, if I replicate the setup in a simple compiled program using the uhd
>> API with all the same settings, this never occurs.
>>
>> So my question is - is the GR scheduler doing something at the beginning
>> of the flowgraph that delays the work() calls and causes overflows, and are
>> there settings I use to mitigate this?  My problem is that once these
>> overflows occur, I can't trust my timing synchronization on the received
>> samples (or have to do further calculations on the rx_time tags).
>>
>> Thanks,
>> Josh
>>
>>
>> _______________________________________________
>>
>>
>> Try specifying "num_recv_frames=128" in your device arguments.
>>
>> Also, are you running this on naked hardware or through a VM?
>>
>>
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>
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